Portable medical devices may be powered by non-rechargeable batteries.
For example, WO 2000/52807 A1, which is incorporated by reference herein, discloses a battery pack comprising a plurality of battery cells, each of them constituting an energy source. Depleted battery cells can be switched with charged battery cells via a battery switching circuit when the monitored voltage falls below a predetermined level.
EP 0982830 A2, which is incorporated by reference herein, discloses a battery pack with a plurality of cells which are, together with a protective circuit, encased in a container. The protective circuit comprises a cell failure detector for each of the cells and a cell interrupter to disconnect a faulty cell.
Accordingly, additional medical devices and medical systems comprising a rechargeable energy supply that is less susceptible to failure, which may be colloquially termed “fail safe” or “single fault safe,” are needed.